This project is aimed at developing new simulation capabilities for elucidating the hemodynamics in intracranial aneurysms. Successful completion of this project will create a systematic and methodical approach to the determination of function in intracranial aneurysms and will provide important new guidance to clinicians as they develop strategies to treat these disorders. The specific aims of these projects are therefore: 1) To determine the impact of experimental imprecision in the specification of CFD models on the computed velocity fields 2) To develop CFD modeling capabilities for predicting regions of intra-luminal thrombus deposition 3) To initiate numerical simulations of flow in a number of patient-specific cerebral aneurysm geometries and initiate a study of the role of hemodynamic descriptors in aneurysm progression. Current advances in medical imaging and computational methods provide an opportunity to use numerical modeling for investigation of the flow in intracranial aneurysms on a patient-specific basis. We propose to combine the state of the art medical imaging with 3D visualization and computational fluid dynamics methods to accurately capture the flow physics and its implications on the aneurysm progression. The objective of this project is to develop a CFD tool for estimating the velocity field in aneurysmal vessels in vivo, and to establish the range of validity of that tool. Relevance to public health: This proposal aims to develop computational methods for assessing blood flow patterns within cerebral aneurysms. These developments will provide the tools needed to determine the impact of flow-related forces to the progression of aneurysmal disease. They will also provide the ability to predict the likely outcome of different surgical interventions, and will provide clinicians with the ability to determine the most effective strategy for treating these disorders. The ability to simulate blood flow patterns in intracranial aneurysms should provide new insights into the underlying physiology that causes some aneurysms to remain stable, and others to grow, resulting in profound symptoms or rupture with a high likelihood of devastating cerebral injury or death.